Carburetors for internal combustion engines

ABSTRACT

A carburetor for internal combustion engines, wherein for the purpose of improving the fuel-and-air mixture a hollow body open in the direction of the suction port axis and having apertures on the peripheral surface is provided in the suction port in front of the fuel outlet, a fuel-and-air-mixture current thereby forming around said hollow body in opposition to the main current in the suction port.

United States Patent 1191 111 3,741,551 Hammerschmied 1 June 26, 1973 v [5 CARBURETORS FOR INTERNAL 1.98l,483 11/1934 Weber 26l/DIG. 39 COMBUSTION ENGINES 3,326,539 6/1967 Phipps 261/78 R 1 4 3,405,917 l0/l968 Hecht 261/D1G. 39 [7 Inventor: Georg c m d, 3,648,988 3/1972 Dibert 261/78 R Schanzelgasse 4, A8010 Graz,

I Austria Primary Examiner-Tim R. Miles 22 June 10 1971 Attorrwy-Watsoh, Cole, Grindle & Watson [21] Appl. No.: 151,714 I '57 ABSTRACT I A carburetor for internal combustion engines, wherein [52] US. Cl... 261/78 R, 261/DIG. 39, 26l/DIG. 67 for the purpose of improving the fuel-and-air mixture [51] Int. Cl; F0211] 29/04 a hollow body open in the direction of the suction port [58] Field of Search 26l/DIG. 39, 78 R, axis and having apertures on the peripheral surface is 261/76, DIG. 67 provided in the suction port in front of the fuel outlet, a fuel-and-air-mixture current thereby forming around 56] References Cited said hollow body in opposition to the main current in UNITED STATES PATENTS the. suction P 1,527,913 2/1925 Payne 26l/DIG. 39 7 14 Claims, 2 Drawing Figures PATEN TED JUN 2 8 I973 3 a I I F 2 H 2 E [1 1. I 1 I i: I &[ !j U L m 5 M 4 a I W n w v) x 0 FIG! INVENTOR 'GEORG HAMMERSCHMIED WATSON COLE GRlNDLE & WATSON 1 CARBURETORS FOR'INTERNAL COMBUSTION ENGINES The invention relates to carburetors for internal combustion engines. It is the purpose of the present invention to provide a type of carburetor incorporating'substantial improvements reducing fuel consumption and increasing engine power.

According to the invention, an insert, open in the axial direction of the suction port, is located in the suction port in front of the fuel outlet communicating with the main nozzle, the said insert consisting of a hollow body provided with apertures over at least part of its peripheral area, and over at least part of its height ar ranged in spaced relation to the inner wall of the suction port. This design tends to produce inside the suction port of the carburetor extraordinary conditions of flow which are conducive to the formation of a definite countercurrent in opposition to the main direction of the air flow, surrounding the main air flow sheathfashion. By means of this countercurrent, vaporized fuel is returned from the area of the suction port adjoining the insert as far as the area of the insert proper, from whence it passes in an opposite direction of flow through the insert apertures into the central main air current.

This mixing process is particularly pronounced when applied in connection with types of carburetors whose balancing air nozzle is located precisely in the countercurrent area. Since the centrally arranged outlet is directed in opposition to the balancing air nozzle, the fuel feed is thereby differentiated.

Actual practice goes to show that if the insert is of appropriate size and has been adapted to suit the type of carburetor used in conjunction therewith, fuel consumption is substantially reduced and the stability of the fuel-and'air mixture in the entire operational area is improved on the one hand, while engine torque is increased as a result of a better preparation of the mixture, on the other hand. I

There is a wide range of different materials which can be used for. the manufacture of the insert, provided the purely mechanical solidity requirements are met. It appears, however, advisable to use a hollow body made of metal in such cases where the occurenceof static charges in the insert cannot be precluded.

According toanother feature of the invention as applied tocarburetors provided with an air flap located .1 in the suction port, it is recommended to arrange the insert in the main direction of the air flow, in front of the air flap. This arrangement has proved particularly effective in actual practice.

According to afurther embodiment of the invention, the apertures inCthe insert may be formed by ducts forming an acute angle with the main direction of the air flow and with the main axis of the suction port. Apertures of this kind serve to intensify the injector effect of the central main air current and consequently, the reversing current in the vicinity of the wall of the suction port. 1

Particularly advantageous is one design of the carburetor, wherein according to the invention the webs pro-.

duced between the apertures or ducts in the insert occupy'only a small portion, preferably only a fraction, of the peripheral area of the insert. Experience also has shown this provision to contribute considerably to the improvement of the mixture formation.

As regards the shape of the insert, various solutions appear to be feasible depending on the type of carburetor used. According to the invention, the use of an insert in the shape of a truncated cone tapering off in the main direction of the air flow has been found to produce particularly favorable results. On account of certain pressure conditions due to changing cross-sections this design is responsible for a more uniform distribution of the air returned in the countercurrent area and enriched with fuel over the entire height of the insert.

According to a further feature of the invention, the insert comprises a second hollow body of the same kind located inside and in spaced relation to the firstmentioned hollow body and also having apertures or ducts over at least part of its peripheral area. As a result, fuel-vapor-enriched air in the area of the insert is subject to greater turbulence.

In certain cases it may be convenient according to the invention to provide the hollow body or bodies with a slot extending essentially in the direction of flow. This serves to produce more uniform flow conditions which are approximately symmetrical in relation to the main sign serves to reduce current losses due to the support of the insert to the minimum.

Other functional advantages are obtained by a carburetor design wherein according to the invention a length of pipe is connected to the interior of the insert, the said pipe extending as far as close to the closed air flap and being directed towards the balancing air nozzle of the main axis. Practical experience goes to show that this design further reduces fuel consumption. Still more advantageous results are obtained by a design wherein according to the invention the pipe is flanged in the proximity of its air-flap end.

Further details of the invention will become apparent from the following description of an embodiment of the invention with reference to the accompanying drawing in which:

, FIG. 1 shows a partially axial cross-sectional view of a carburetor, limited to the area which is essential for the invention, and

FIG. 2 is a top plan view of the carburetor shown in FIG. 1.

The carburetor 1 shown in a partial and strongly simplified view only carries a cover 2 screwed to the carburetor housing with the interposition of a gasket 3. The float chamber of the carburetor is designated by reference number 4, the float by 5 and the fuel feed pipe to the float chamber by reference number 6. Into the suction port 7 of the carburetor housing protrudes the outlet arm 8 with the outlet 9 connected to the main nozzle (not shown in the drawing) of the carburetor. The outlet 8 is arranged approximately in the middle of the suction duct 7'and terminates in the direction of the main air current indicated by arrow 10. The balancing air nozzle 12 of the carburetor is screwed into the connecting bore 11 emerging from the main nozzle and arranged in eccentrical relation to the main axis of the suction port 7.

In the section of the suction port 7 located in the carburetor lid 2 the air flap 13 (shown in its open state) is rotatably mounted. Its closed position is indicated by dotted lines. Into the suction port 7 protrudes also the inclined air-vent pipe 14 of the float chamber 4. Connected to the inlet connection 15 of the carburetor cover is the air feed pipe 16 (only partially shown in the drawing) slid on to the inlet connection 15 and clamped down in a manner not particularly illustrated by the drawing. The air feed pipe 16 is usually an integral part of the air filter housing of the internal combustion engine.

In the suction port 7 above the air flap 13 an insert 17 is located, which in the embodiment shown comprises two hollow bodies 18 and 19 in the shape of truncated cones and arranged in concentrical relation to each other and to the main axis of the suction port 7. Over at least part of their peripheral area, the hollow bodies 18 and 19 are provided with apertures 20 forming ducts which form an acute angle with the main axis of the suction port 7. In their plainest form according to the invention, the hollow bodies 18 and 19 are made of expanded metal whose meshes constitute ducts having the required inclination. The hollow bodies 18 and 19 are interconnected by means of radial struts 21 (in the present instance, three struts arranged in staggered relation to each other forming angles of 120 respectively) and the outer extremities of these struts 21 are inserted in recesses 22 provided on the upper rim of the inlet connection 15. Connected to the interior of the insert 17 is a pipe 23 arranged in eccentric relation to the main axis of the suction port 7 and extending as far as close to the closed air flap 13 and carrying a flange 24 in the proximity of its air-flap end. The pipe 23 has a lateral recess 25 into which the free extremity of the air-vent pipe 14 protrudes.

In the area of the suction port 7, this arrangement of the insert 17 produces particular flow conditions indicated by arrows in FIG. 1, which are responsible for the formation of a pronounced countercurrent zone in the vicinity of the wall of the suction port 7. This countercurrent zone surrounds the main air stream 10 sheathfashion and is instrumental in lifting the fuel vapors from the area of the air balancing nozzle 12 and in returning same to the area of the insert 17. The fuelenriched counter-air-current arrives at the apertures 20 of the hollow bodies 18 and 19 and as a result of the injector effect of the central main air stream 10, accompanied by a reversal, passes through the apertures 20 and mixes with the main air current.

These particular flow conditions produce a differentiated fuel feed resulting not only in a substantial reduction in fuel consumption in addition to greater stability of the fuel-and-air mixture over the entire operational area, but also in consequence of improved mixture formation in an increase of the torque of the internal combustion engine fed by the carburetor. It has been found in actual practice that the nozzle extension formed by the pipe 23 and its flange 24 and directed into the area by the side of the balancing air nozzle 12 contributes essentially to the reduction of fuel consumption.

A number of variants of the embodiment of the invention hereabove described with reference to the accompanying drawing are possible within the scope of the present invention. In particular, there is no limitation as to the design and shape of the hollow body or bodies forming the insert 17.

I claim:

1. A carburetor for internal combustion engines comprising a suction port, a main fuel nozzle, a pipe emerging from the said main nozzle and terminating in the said suction port with a fuel outlet, an insert, open in the direction of the axis of the said suction port, located in the suction port in front of the said fuel outlet and consisting of a hollow body, having apertures at least over part of its peripheral area and arranged in spaced relation to the inner wall of the said suction port at least over part of its height.

2. A carburetor as claimed in claim 1, having an air flap arranged in the said suction port in front of the said fuel outlet, the said insert being located in the main direction of the air flow in front of the said air flap.

3. A carburetor according to claim 1, wherein the said apertures of the insert are defined by ducts forming an acute angle with the main direction of the air flow and with the main axis of the said suction port.

4. A carburetor as claimed in claim 1, comprising struts formed between the said apertures of the insert, the said struts occupying a minor portion of the peripheral area of the said insert as compared with the size of the said apertures.

5. A carburetor according to claim 1, wherein a hollow body in the shape of a truncated cone tapering off in the main direction of the air flow and constituting the said insert is provided.

6. A carburetor according to claim 1, wherein the said insert comprises a second identical hollow body located inside and in spaced relation to the firstmentioned hollow body and likewise having apertures at least over part of its peripheral area.

7. A carburetor according to claim 1, wherein a slot is provided in the said hollow body, the said slot extending essentially in the same direction as the direction of the air flow.

8. A carburetor according to claim 6, wherein a slot is provided on each of said hollow bodies, the said slots extending substantially in the same direction as the air flow.

9. A carburetor according to claim 1, comprising an inlet connection, outwardly protruding arms mounted on the said hollow body, the outer extremity of the said arms resting upon the said inlet connection.

10. A carburetor according to claim 6, comprising an inlet connection, outwardly protruding arms connected with both hollow bodies,'the outer extremity of the said arms resting upon the said inlet connection.

11. A carburetor according to claim 2, comprising a length of pipe attached to the said insert and adjoining the interior of the said insert, the said pipe extending as far as close to the said closed air flap.

12. A carburetor according to claim 11, comprising a balancing air nozzle in the said suction port, the said pipe being directed towards the said balancing air nozzle.

13. A carburetor according to claim 11, wherein the said pipe is directed towards the main axis of the said suction port.

14. A carburetor according to claim 11, comprising a flange provided on the said pipe near the extremity of the pipe facing the said air flap. 

1. A carburetor for internal combustion engines comprising a suction port, a main fuel nozzle, a pipe emerging from the said main nozzle and terminating in the said suction port with a fuel outlet, an insert, open in the direction of the axis of the said suction port, located in the suction port in front of the said fuel outlet and consisting of a hollow body, having apertures at least over part of its peripheral area and arranged in spaced relation to the inner wall of the said suction port at least over part of its height.
 2. A carburetor as claimed in claim 1, having an air flap arranged in the said suction port in front of the said fuel outlet, the said insert being located in the main direction of the air flow in front of the said air flap.
 3. A carburetor according to claim 1, wherein the said apertures of the insert are defined by ducts forminG an acute angle with the main direction of the air flow and with the main axis of the said suction port.
 4. A carburetor as claimed in claim 1, comprising struts formed between the said apertures of the insert, the said struts occupying a minor portion of the peripheral area of the said insert as compared with the size of the said apertures.
 5. A carburetor according to claim 1, wherein a hollow body in the shape of a truncated cone tapering off in the main direction of the air flow and constituting the said insert is provided.
 6. A carburetor according to claim 1, wherein the said insert comprises a second identical hollow body located inside and in spaced relation to the first-mentioned hollow body and likewise having apertures at least over part of its peripheral area.
 7. A carburetor according to claim 1, wherein a slot is provided in the said hollow body, the said slot extending essentially in the same direction as the direction of the air flow.
 8. A carburetor according to claim 6, wherein a slot is provided on each of said hollow bodies, the said slots extending substantially in the same direction as the air flow.
 9. A carburetor according to claim 1, comprising an inlet connection, outwardly protruding arms mounted on the said hollow body, the outer extremity of the said arms resting upon the said inlet connection.
 10. A carburetor according to claim 6, comprising an inlet connection, outwardly protruding arms connected with both hollow bodies, the outer extremity of the said arms resting upon the said inlet connection.
 11. A carburetor according to claim 2, comprising a length of pipe attached to the said insert and adjoining the interior of the said insert, the said pipe extending as far as close to the said closed air flap.
 12. A carburetor according to claim 11, comprising a balancing air nozzle in the said suction port, the said pipe being directed towards the said balancing air nozzle.
 13. A carburetor according to claim 11, wherein the said pipe is directed towards the main axis of the said suction port.
 14. A carburetor according to claim 11, comprising a flange provided on the said pipe near the extremity of the pipe facing the said air flap. 